Continental Flight 128, en route from Rio de Janiero to Houston on 3 August, encountered severe turbulence over the Atlantic Ocean just north of Hispaniola, according to AP Press reports. Other press reports suggest the turbulence occurred southeast of Puerto Rico (see this one from Bloomberg, for example), but flight tracking software available online shows a flight path that changed north of Hispaniola, presumably in response to the turbulence encountered. The aircraft landed in Miami at 5:30 EDT, or 0930 UTC; according to press reports, the turbulence was encountered an hour before that, or around 0830 UTC. [UPDATE: on-board flight logs (courtesy of John Williams at RAP at NCAR) suggest the flight path change, presumably right after the encounter with turbulence, occurred around 0800 UTC; that data has been superimposed on GOES-12 Imager water vapor (shown above) and window channel imagery (linked below)] What was happening in the satellite imagery at the time?

Cloud-top cooling (below) estimated using the UW/CIMSS Convective Initiation algorithm indicate cooling of 13 K in 15 minutes. Assuming a moist adiabatic atmosphere with a lapse rate of 6.5 K/km, this is vertical growth of 2 km in 15 minutes, equivalent to upward motion exceeding 200 cm per second. The flight data (the dashed line in the figure below) suggest that the airplane flew very close to this developing cumulus tower.